This invention relates to new and useful improvements in adjustable scaffolds, particularly adjustable scaffolds such as those illustrated and described in U.S. Pat. No. 3,396,817 dated Aug. 13, 1968.
In this U.S. patent, a locking device is provided between the platform mounting portion and the leg around which the mounting portion extends. It includes a spring loaded pin which can be withdrawn from an aperture within the leg thus allowing the platform to slide relative to the leg whereupon the pin is released and the spring engages the pin within the selected aperture thus supporting the platform relative to the leg. Means are provided to lock the pin in the engaged position and take the form of a nut device which is rotated upon the pin and screw threadably engages a fixed portion on the platform so that the pin cannot vibrate or be moved to the disengaged position unless the nut is unscrewed from the fixed screw threaded portion. Unfortunately, the nut is difficult to manipulate into engagement with the screw threaded portion due to the fact that a mounting shroud for the pin surrounds the pin and the nut. It is particularly difficult to manipulate the nut in cold weather when the operator is wearing gloves and the like so that it is normal for operators not to bother with the safety device, namely engaging the nut with the fixed screw threaded portion in order to prevent an inadvertent withdrawing of the pin and the subsequent collapse of the platform.
The result has been several accidents in which the platform has collapsed at one end thus allowing materials and operators or workmen to be spilled from the platform and although such platforms are often operated at a relatively low height from the ground, nevertheless they can be situated at a considerable distance above the ground so that injuries have occurred not only to workmen or operators falling from the platform, but due to material falling from the platform and striking personnel situated close to or below the platform.